1. Field of the Invention
The present invention relates to a testing method and testing apparatus for evaluating the light fastness of a liquid crystal panel.
2. Description of the Related Art
Conventionally, a light fastness test is performed on a liquid crystal panel as a way of evaluating the reliability of the liquid crystal panel. For example, when a liquid crystal panel used as a light bulb in a liquid crystal projector is irradiated with intense light over a long time period, the various constitutional elements (components, members) thereof are likely to deteriorate, and it is therefore important to perform a light fastness test to ensure the required quality of these elements.
To test the light fastness of such a liquid crystal panel, a test period of up to several months may be required after the order is made. However, with demands being made for ever shorter product development periods, such a long test period is unacceptable. In response, a so-called acceleration test, in which a test is performed under more severe conditions than an actual usage situation and deterioration over long-term usage is predicted on the basis of the test results, is known as a method of shortening the evaluation period. The prior art relating to this type of light fastness evaluation of a liquid crystal panel is disclosed in Japanese Unexamined Patent Application Publication 2001-4526, for example.
In a conventional light fastness evaluation method such as that described above, a liquid crystal panel is irradiated with light using a light source such as a metal hydride lamp, UHP lamp, or halogen lamp. However, the light obtained from these light sources is poorly condensed, and hence a high energy density cannot be obtained. As a result, it is difficult to elicit a deterioration phenomenon in a short amount of time. Thus a problem arises in that a long time period is required to evaluate the light fastness of the liquid crystal panel. This long evaluation period makes it difficult to reduce the product development period, which is undesirable.